Before you can install PHPUnit you need to have installed PEAR. If that is not the case , you can do the following:

Go to wamp-directory, b.v. :C:\>cd wamp\bin\php\php5.3.0

To install PEAR, execute the following command:C:\wamp\bin\php\php5.3.0>go-pear.bat
You will be asked several questions which you can leave to the default value.

The next thing you will need to do is register PEAR environmental variables in the registry. Therefore you can execute C:\wamp\bin\php\php5.3.0>PEAR_ENV.reg (Perhaps not a bad idea to backup your current registry!). Now you can call PEAR everywhere on the command line

If you cannot call PEAR on the command line, you will need to add the PEAR directory to the Windows environmental ‘Path’ variable. You can find that one in: System Properties -> Advanced-> Environment Variables. Select the ‘Path’ variable, click on ‘Edit’ , and add to the end of the line a ‘;’ and the path to the PEAR directory which in my case is: C:\wamp\bin\php\php5.3.0